The present invention is a process for the preparation of tricyclo-[3.3.1.1.sup.3,7 ]dec-2-yl- [R-(R*,R*)]-3-(1H-indol-3-ylmethyl)-3-methyl-4,9-dioxo-7,11-diphenyl-10-ox a-2,5,8-triazaundecanate of the formula: ##STR1##
This compound is a key compound in the preparation of a new class of highly selective and orally effective gastrin and CCK-B antagonists (see D. C. Horwell et al, J. Med. Chem., 1991;34:404-14. The compounds, their preparation, methods of using them, and compositions containing them are found in U.S. Ser. No. 07/629,809, filed Dec. 12, 1990 hereby incorporated by reference. The final products are useful as pharmaceutical agents in the treatment of anxiety, appetite disorders, excess gastric acid secretion, gastrointestinal ulcers, psychoses reaction caused by drug or alcohol withdrawal, cocaine, benzodiazepine, or nicotine withdrawal to potentiate the effects of morphine, pain, and depression for cognition.
It is an object of the present invention to provide an economical process, which can be carried out on a technical scale, for the preparation of this compound with a high degree of purity.